A recent meta-analysis of 800 per reviewed studies by the Task Force on Systemic Pesticides shows that neonoics are a key factor in the decline of honey bees worldwide. The analysis has also shown harmful effects to earthworms, butterflies, birds, soil microbes and other organisms essential to food production.

However, a report released today by Friends of the Earth shows that more than half of the plants sold as “bee friendly” by garden centers at Lowe’s, Home Depot and Walmart contain neonics. Of the 71 samples collected in 18 cities in the United States and Canada, 36 (51 percent) contained neonicotinoid pesticides. Some of these contained pesticide levels high enough to kill bees outright and 40 percent of the positive samples contained two or more types of neonics.

“The high percentage of contaminated plants and their neonicotinoid concentrations suggest that this problem continues to be widespread. Most gardeners have no idea that their gardens may be a source of harm to bees. We’re calling on retailers to get neonicotinoid pesticides out of their plants and off their shelves as soon as possible. Until then, gardeners should buy organic plants to ensure the safety of bees,” said Lisa Archer, director of the Food & Technology program at Friends of the Earth-U.S. in a statement.

The worldwide decline of honey bee populations could have serious consequences for the global food supply and for agricultural economies. Honey bees, along with other pollinating animals, are essential to two-thirds of the world’s food crops.

The European Union placed a two year ban on most neonics and the United States Food and Drug Administration (FDA) is facing growing pressure to enact restrictions of their own.

According to Friends of the Earth, a growing number of retailers are taking action on their own without waiting for government action. The list includes most UK garden retailers such as Homebase, B&Q and Wickes. It also includes a small but growing number of US retailers, nurseries and landscaping companies.

Today BJ’s Wholesale Club which operates 200 locations in 15 states announced that it will remove neonics or place warning labels on plants containing them by the end of 2014.

“A growing number of responsible retailers have decided to be part of the solution to the bee crisis and are taking bee-harming pesticides off their shelves. We urge Home Depot, Lowe’s and other major retailers to join these leaders in making our backyards and communities safe havens for bees,” said Archer.

The report, “Gardeners Beware 2014” is available as a free download.